Remote control system



June 24, 1930. M, L. NELSQN 1,765,538

REMOTE CONTROL SYSTEM Filed Nov. 16. 1921 `s sheets-933er 1 4 rc2/ease m June 24, 193. M, L, NELSQN 1,765,538

REMOTE ACONTROL. SYSTEM Filed Nov. 16'. 1921 e sheets-sheet 2 June 24,v 1930. QM. NELSON 1,765,538

REMOTE CONTROL SYSTEM Fired Nov. 16. 1921 6 Sheets-Sheet 3 June 24, 1930. M. l.. NELSQN 1,165,538

'REMOTE CQNTROL sYsTxgzu Filed Nov, 16, 1921 6 Sheets-Sheet 4 *Imran cfr-.- l

June 24, 1930. M. L.. NELSON REMOTE CONTROL SYSTEM Filed NQv 16, 1921 b Sheets-Sheet 5 6 Sheets-She'et Filed Nov. 16.' 1921 @Ag/Q Patented June 24, 1930 uNlrEDf-srATEsl PATENT oFFlcl;

MARTIN L. NELSON, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO AUTOIATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE animera CONTROL SYSTEM Application led November 16, 1921. Serial No. 515,664.

The present` 'invention relates to remote control systems in general, but is more particularly concerned with remote control systems that may be used in connection with 6 electric substations; and the principal object, brieiiy stated, is the provision o'f such circuit arrangements as are necessary in order to put such a remote controlsystem into effect-ive operation. v

Other objects have to do with the renement of the Various circuits used so as to make them more-efficient and desirable.

Still another object is to eect the desired control with the use of the smallest possible number of circuits between the apparatus to be controlled and thel point from whi'ch it is controlled. f i

These objects, together with others which will not be specifically-mentioned now, will be pointed out and explained fully hereinafter in connection with the accompanying drawings comprisin Figs. 1-10, inclusive, n order to enable t e system to'be readily understood, Figs. 1, 3and 5 should be ar- /15 ranged in order, with Fig. 2 overFig. 3 and with Fig. 4: over Fig.' 5, and, with the corresponding lines in alignment.

The apparatus shown in Fig. 1 and in the left hand side of Fi 2 is located in the c'ontrolling station whic will be referred to hereinafter as the despatchers oiice. riihe' remaining equipment shown in Fig. 2, together l with all the equipment shown in Figs. 3, d and 5, is located 1n the substation, which is connected with the despatchers oce by two pairs of conductrs and 61, and' 83 and 84, as shown. The necessary control over the apparatus in the substation is exercised over the circuit composed o' the pair of conductors shown in Fig. 2, and the signals indicative of the condition of the ap aratus at the substation are received over t e other pair of conductors, Figs. 1 and 3. The despatchers oce is assumed to contain duplicate r equipment for every othersubstation in the system.

The substation shown is assumed to be pro.- vided for the purpose of. supplying current to a trolley -wire of an interurban electric line and may belocated at some point along the line between two main stations, two similar slbstations, or a main station `and an; other substation. J As shown, the motor gen'- erator MG', Fig. 4, is in operation andthe grounded generator of the unit is sup lying current to the bus bar 238 by way of tiie cir-4 cuit breaker CB". The bus bar 238 is connected with the trolle wire 235 by way of the circuit breaker C The motor of the motor generator MG is supplied with three phase alternating current 'from the high tension mains comprising conductors 350-352," inclusive, Fig. '5, by way of theassociated transformer bank, low tension mains 347-349, inclusive, circuit breaker CB, and the starter S.

rlhe motor generator MG may be placed in service by closing the circuit breaker CB1, Fig. 5; operating the starter S so asao bring the unit up to speed; and then closing the circuit breaker CB2 which connects the gen-y erator of the motor generator MG to the bus bar 238. f

The controlling switch D', Fig. 2, and the signal operating switch D, Fig. 1, are mechanically ofthe type of automatic switch disclosed in Automatic Telephony, by `Smith and Campbell, 'a book published by McGraw- Hill Book Com any, 370 Seventh Avenue, New York, N. second edition. A photoaph of sucha switch is shown on page 55 of this publication and a skeleton drawing is shown on page 58. A description will be found accompanying the photograph. The circuits of theseswitches are shown complete and will be described fully hereinafter.

The circuit interrupter Fig. 2, associated with the relay groupRG may be mechanically similar to the automatic sender or calling device shown on pages 40 andA Lil o'f Automatic relephony above referred to. The

' function of this interrupter is to control the switch D', with which it is connected by means of the two conductors 83 and 84 through the medium of the relay group RG. The circuits and functions of the relay group RG will be pointed 'out and explained more fully hereinafter.

Ilihe apparatus shown in Fig. 3 is actuated by the various devices shown in Figs. 4, and le v through the medium of the relay group RG.

The contact making switch C, Fig. 3, comprises two semi-circular rows of contacts which are wiped over by the wipers 167 and 168 as shown. These two wipers are rigidly secured to a common spindle and are operated by the stepping magnet 165 by means of which they are stepped' from contact to contact asl the magnet is alternately energized and dcenergized. One mechanical embodiment of such a switch is shown on page 51 of Automatic Telephony, hereinbefore reerred to.

For each different pieceof apparatus in the substation such as starters, circuit breakors, etc., there appears in the despatchers 0f 1 tice three indicating lamps, such as the lamps L', L2 and L, together with a controlling key and relay, as shown, Fi 1. In the case o a circuit breaker, one of t e three lamps is lighted as long as it is thrown in and another lamp is lighted as long as it is tripped. When the circuitbreaker changes position the lamp that is lighted goes out and the other lamp lights. At the same time the third lamp of the group becomes lighted to attract the attention of the despatcher to' thefact that a change has occurred in that particular group of lamps. Each time a signal comes in, a common buzzer is operated 40` to attract the attention of the despatcher,

and in order to direct the lattention of the "despatcher to the si als of the substation from which the signa has come, a pilot lamp common to the signals pertaining to thev substation in question is lighted. The despatcher is provided with a push button to shut off the buzzer and extinguish the ilot lamp and other push buttons one of w ich is used to extin ish the third lamp of the group of three amps in which the change has taken place.

The overload control system comprising4 .the'relay grou RG and the motor M, Fig. 4, is provide for the purpose of giving emergency service by cutting the motor generator MG into service when the load bef comes too much for the other-unit and for cutting the unit MG out of service again when the load becomes small enough :for the motor enerator MG to carry alone. The

overloa control system, however, is normally inoperative and is placed in service automatically in case either of the two circuits between the despatchers oice and the o5 substation is accidentally opened, during the storm for example. The lamps L7 and L are provided for the purpose of informing the despatcher when either of the two circuits between the despatchers oilice and the ,substation goes open accidentally.

. Figs. 6, 7, and 8 show three modifications of the arrangement shown in Fig. 1 for receiving signals from the substation.

Fig. 9 shows a remote controlled ammeter which is located in the despatchers oilice and controlled by the contact making ammeter A, Fig. 4. The manner in which this control is effected will be explained more fully hereinafter.

Fig. 10 shows certain signalling and recording mechanism that may be installed in a substation that differs from the one shown only in that the operations performed by the despatcher do not alect the devices at the substation directly but inform an attendant what to do.

It is to be understood that, while there are shown a plurality of batteries in the drawings, there need be only one battery in the substation and one in the despatchers office, the several batteries being shown for the sake of simplicity only.

The apparatus, having been described in general, will now be described in connection with a detailed description of its operation. For this purpose, it will be assumed that the despatcher, having been informed by the ammeter shown in Fig. 9 that the load in the substation is high enou h to warrant the startingof another mac ine, decides to put the motor generator MG, F1 4, into o eration so as to supply current g r the tro ey wire 235 in multiple with the motor generator MG. In order for the despatcher to do this he must iirst operate the circuit breaker CB* so as to connect up the leads 347-349, inclusive, t o the starter S. In order to throw in the circuit breaker CB the despatcher must causethe control switch D', Fi 2, to place ground momentarily on its ban contact in which conductor 116 terminates. This is done by manipulating the dial of the interru ter I associated with the relay group RG; rst inaccordance with the level of bank contacts of the switch D in which conductor 116 terminates, the fifth level for exam le; and then in accordance with the partie ar contact in that level which is the contact 111'. When the dial of the interrupter I is `moved from its normal position, the sprin 65 is allowed tol Icome into engagement with its associated contact, thereby closin a circuit for. slow releasing relay 69, inclu ing armature 79 and its resting contact. Relay 69, upon energizll,

'pre ares a circuit for relay 70 at .armature an at armature 77 closes. a circuit for slow releasing rela 68. Relay 68, u ing, removes t e ground potenti 'from armature 73 andprepares a circuit for rela 72 at armature 76, and at armature 75 plhces a energizshunt around the high woundnormally ener.-

gi'zed relay 67. Relay A67, upon deenergizing,

line relay 90 energizes in response to the shun-ting out of the Ahigh wound relay 67 in the despatchers oice and closes a circuit for the slow releasing release relay 92 at armature 99. VSlow release relay 92, upon energizing, opens a point in the circuit of release magnet 95 and prepares a circuit forvertical magnet 96 at armature 105; places ground v tact of armature 100 and.l

upon wiper 98 at armature 103 and at armature 104 removes ground from the resting conlaces av shunt around the normally energize relay 91. This isdone so as to afford a better circult for relay 90. Relay 91 deenergizes but does not perform any function at this time.

g for vertical ma l' v net 96 to As the dial of the interruptor I in the despatchers oice returns to normal position, the circuit ofline relay 90 of the switch D is interrupted-at the contacts 66 a number of times corresponding 5to the number for which the dialv was operated which in this case is assumed to be -five. Each time line relay'90 deenergizes, it opens the circuit of slow releasing release relay 92 but the said relay does not have time to fall back before its circirc'uit is closed again upon the next energization of relai 90. As a further result of each deenergization of relay 90 it closes a circuit et 96 as follows: From ground by way o armature 99 and its resting contact, armature 105 and its working contact,.the contact of o normal spring 102 and said spring, series relay 93, and vertical magattery. Bythe operation of vertical magnet 96, the shaft and wiper of the switch D are raised step b step until the latter-stands' opposite the th level o con- 4 y tact's. Relay 93 is energized in series with the vertical magnet 96 and being/slow releasing retains its armaturel106 attracted throughout the'vertical movement, thereby maintaining` its own circuit and that of vertical magnet 96 intact after the od normal springs lOl-102 have shifted as they do upon the first vertical step. yAt the ond of the series of interruptions, line relay 90 comes to rest in an energized condition and slow releasing relay 93 upon deenergizing, transfers the operating circuit from vertical magnet 96 to the rotary magnet 97.

In the despatchers' office, the dial of the in-` terrupter I, upon reaching normal position,

opens the initial circuitof relay 69 at spring 65, lwhereupon relay. 70 energizes in series with relay 69 over a circuit which extends from ground by way of the resting contact of f armature 82 and said armature, relay 70,

working contact of armature 78 and -said armature and relay 69 to battery. Relay 69 is maintained energized in series with relay of the contact in the fifth level of the switch D in which the conductor 116 terminates 'and since the said contact, which is the contact 111, is the third contact in the level, the number for which the despatcher turns the said dial is 3. As soon as the dial of the interrupter I is moved from its normalposition, spring 65 completes a circuit for slow releasing relay 71, which circuit includes armature its Working contact. Relay 71, upon energizing, disconnects armature 73 of relay 67 at armature 81 and at armature 80 prepares a circuit for relay 72. The dial of the interrupter I in turning to normal position causes the contacts 66 to be separated three times, thereby producing three interruptions in the circuit of line relay in the switch D. Each time line relay 90 dcenergizes in response to lone of these interruptions, it closes a circuit by Way of armature 99 and its resting contact,

armature and its working contact, normally opencontacts controlled by off normal spring 102, armature 106 and its resting contact, and rotary magnet 97 to battery. By the operation of rotary ma net 97, which receives three impulses at this time, the wiper 98 is rotated into engagement with the third contact in the iifth level which is the bank contact 111. Slow releasing relay 94 is maintained energized throughout the rotary movement in multiple with rotary magnet 97 and at armature 107 maintains the wiper 98 disconnected. At the end of the rotary movement, slow acting relay 94 deenergizes and connects -up the wiper 98 at armature 107,

thereby closing the following circuit for the 'solenoid 341 of the circuit breaker C134: 'from ground by way of the working contact of armature 103, resting contact of armature 107 and said armature, wiper 98, bank contact 111, conductor 116, and solenid 341 to battery. Solenoid 341, upon energizing,v

llO

initial circuit of slow releasing relay 71, whereupon relay 72 energizes in series with relay 71 over a circuit which extends from ground, by way of armature 76 and its working contact, relay 72, armature 80 and its working contact, and relay 7l to battery. Relay 71 is maintained energized in series with relay 72 and the latter, upon energizing, opens the circuit of relays 69 and 70 atarinature 82. Relay 70 deenergizes immediately but does not perform any particular function at this time. Relay 69, being slow releasing, is maintained ener ized for an interval and, upon finally falling back, opens the circuit of slow releasing relay 68 at armature 77. Relay68 also maintained energized for an interval after'its circuit is opened and, upon finally fallin back, removes the shunt from around the igh wound relay 67 at armature 75 and at armature 7 6 opens the circuit of relay 72 and places ground upon armature 81. Relay 72 deenergizes iinmediately but does not perform any function at this time. Relay 71, being slow releasing, holds its armature attracted long enough to permit the high wound relay 67 to energize before it replaces ground upon armature 73 at armature 81.

In the substation, line relay 90 of the-switch D', being marginally adjusted, retracts its armature responsive to the removal of the shunt from around the high wound relay 67 of the'relay group RG, thereby opening the vcircuit of slow release relay, 92 and closing the previously traced operating circuit for rotary magnet 97.. Rotary magnet 97 and relay 9 4 energize simultaneously. The energizetion ofrelay 94 serves to disconnect the wiper 98 at armature 107 and also to disconnect the restin 108.

contact of armature 100 at armature he rota magnet 97, upon energizin advances the Wiper 98 into engagement wit Aeo bank contact 112. This however, does not have any articular function at this time, being mere y an incidental operation. Slow releasingl relay 92 upon deenergizing, removes t e shunt rom around relay 91 at armature 104; disconnects ground from the resting contact of armature.107 at armature A103; and at armature 105 opens the operating circuit whereupon rota energizes.

magnet 9 7 de- As a. further resu t of the deenerzation of release relay 92, it closes a circuit or release ma and its resting contact. B the operation of release magnet 95, the sha vand wiper of the switch D' are restored to normal position, the circuit of release magnet 95 being o at off-normal contacts 101 bythe switch shaft when it reaches normal position. Relay 94 which, as before stated, is slow releasing maintains the resting contact of armature 100 disconnected at' amature 108 until after relay 91 has energized inresponse to the reet 95 at armature'105 includcontacts 101 andarmature 99V which comprise three relays each, such as t e one shown in the upper left hand corner of the sheet and comprising relays 203, 201, and

205, when actuated b a ground potential on the associated control7 conductor, such as the conductor 301, causes the switch D in the des patchers oilice to be prepared for operation in a manner to be explained fully hereinafter, after which two series of interruptions are produced in the circuit of the line relay of the said switch D. This o ration is identically 'the same no mattei-which relay group is actuated, inasmuch as the production of two series of interruptions in the circuit of the line relay of the switch D is concerned, but differs in the number of interruptions produced. The minimum number vof interruptions produced in any one series .is` one and the maximum number is 1ten. There are 100 such relay groups but, to avoid complicating the drawings unnecessarily, only four them have been shown. The relay groupl in the upper left hand corner of Fi 3, w en actuated, sends in the number 11, w 'ch means that each of the two series of interruptions .produced comprises lonly a. single interru tion. The second number 12 which co prises one interruption in the first series and two in the second. The following groups of relays that send in the 'numbers 13-68, inclusive, have been omitted in the drawings and the third group shown sendsin the number 69. The forth rela group shown sends in the number 60 whi comprises six interni tions in the first series ay group sends in t e and ten in the secon series. The following relay grou s which send in the numbers 71-00, inclusive, ave been omitted in the drawings. The number 00, it may be said, comprises ten interruptions in each series.

It will be understood that the dotted portions Yof the conductors extending between the second number sending group of relays and the third indicates that they pass through chain contacts on the intermediate relay sets maratea explained. As a further result of the operation of member 343, the ground potential is removed from conductor 304 and placed upon conductor 303. In response to the removal of the ground potential from conductor 304, relay 170, Fig. 3, deenergizes and at armature 171 connect-s conductor 304 'with relay 172. This, however, does not produce any result at this time. As a lresult ofthe ground potential being placed on conductor 303, a circuit is closed for relay 174. Re lay 174, upon energizing, closes the following circuit for relay 17 5: `from ground by Way of armature 148 of relay 132, which relay is located in the relay group RG', and the. resting contact of the said armature, conductor 186 armature 183 and its resting Contact,

armature 184 and its resting contact, similar armatures and contacts .on intermediate relays, (not shown) armature 177 and its working contact, normally closed contacts controlled by armature 177, and relay 17 5 to battery. Relay 175, upon energizing, closes a locking circuit for itself and opens its initial circuit at armature 178, the said locking circuit being as follows from ground b way of the normally closed contacts control ed by armature 146 of relay 131, which relay is located in the relay roup RG', conductor 187, armature 212 and its resting contact, armature`213 and its resting contact, armature 178 and its working contact, and relay 175 to battery. As a further result of the energization of relay 17 5 it closes a circuit for relay 173`at armature 180, whereupon relay 173 attracts armature 176, thereby opening the circuit of relay 174 and closing a lookin circuit for itself. Relay 174, upon deenergizmg, closes the chain contacts again at armature 177. As a still further result of the energization of relay 17 5 it connects the sixth impulse stop conductor 196 with the' first digit stop conductor 188 at armature 181; connects the ninth impulse stop conductor 199 with the second digit stop conductor 189 at arma-ture 182; and at armature 179 places ground upon the start conductor 190, thereby closing a circuit for the slow releasing relay 132. Relay 132, upon energizing, disconnects ground at armature 148 from conductor 186 and consequently from the chain of armatures and contacts including armatures '183.l 184, etc. This is done so as to render ineli'ective the ener ization of any of the relays 201, 202, etc. unt after the operations, necessary to inform the despatch'- er that the circuit breaker @B4 has been successfully thrown in, have been completed.

As a further result of placing ground upon start conductor 190 a circuit is closed for slow irelcasing relay 130, including/armature 140 and its resting Contact. .Slow releasing relay 130, upon energizing, places ground upon armature 146 of relay 131 at armature 143, and places a shunt around the high Wound induction.

normally energized relay 129 at armature 144. The said relay 129 holds its armature 142 attracted for a slight interval thereafter owing to the slow releasing effect caused by its self As aurther result of the energization of relay 130, it closes a circuit for slow releasing relay 131 at armature 145. Relay 131, upon energizing, disconnects ground from armature 142 of relay 129 at armature 147 before the latter relay has had time to tall back, and at the same armature 147 places ya multiple ground uponthe starting conductor 190 for a purpose that will be more apparent later. As a further result of the energization of slow releasing relay 131 it shifts the conductor 187 from ground, by way of the normally closed contacts controlled by armature 146, te ground, by way of the working contact 0:? armature 146 and said armature, and armature 143 and its working contact.

In the despatchers oce, the marginally adjusted line relay 39 of the switch l) energizes in response to the placing of the previously mentioned shunt around the high resistance normally energized relay 129 of the relay group R and closes a circuit for release relay 37 at armature 57. Release relay 37 upon energizing, opens a point in the circurtof release magnet 42 and prepares a cir- 95 cuit for vertical magnet 40 at armature55; places ground on wiper 58 at armature 54; and at armature 53 removes ground from armature 56, at the same time placing a shunt around the normall energized relay 38. Relay 38 deenergizes ut does not perform any articular function at this time. The switch D is now ready to be operated in the same manner as the switch D".

Returning now to the relay group RG in the substation, as a still further result of the placing of ground upon start conductor 190 the following circuit is closed: from ground by way of conductor 190, armature 140 and its resting contact, resting contact of armature 153 and said armature, impulse relay 133, the Contact of sprin 156 and said spring, and resistance 158 to attery. The spring 156 is alternately moved out ot engagement with and brought into engagement with its associated contact by the motor driven cam 157 and consequently after the above traced circuit is closed for relay 133 the said relay is energized and deenergized once during each revolution of the cam-157. Each time relay 133 energizes it closes the circuit of steppincr magnet 165 of the im ulse counting switch at armature 159. tepping magnet 135, upon energizing the first time, attracts its armature, thereby causing the assoc1ated pawl to en age another notch on theratchet wheel. W en relay 133 deenergizes, 1t opens the circuit of stepping magnet 165 at armature 159, whereupon the sai stepping magnet deenergizes, thereby rotating the wipers 167 contacts. `The rotation of wi the shunt from around armature 149 and its resting contact of impulse relay 133 at armature 150. This does not have an immediate effect, however, owing to the act that impulse relay 133 has just fallen back and consequently armature 149v is in engagement `With its restin contact. The next time relay f 133 energizes,1n response to the closure of its wit its secon circuit by the revolving cam 157, it opens the bridge across conductors and 61 at armature 149 and consequently interru ts the circuit of line relay 39 of the switc D in the despatchers oice. .As a further result of the energization of relay 133 it closes a circuit for stepping magnet 165 of the switch C and the sai stepping magnet,'upon energizing, causes the associated pawl to en age anot er notch on the ratchet'wheel. Vhen the circuit of impulse relay 133 is o ened again, it, u on deenergizing, closes the ridge across con uctors 60 and 611at armature 149, and at armature 159 opens the circuit of stepping .magnet 165 of the switch C, whereupon the wipers 167 and 168 are advanced into en.- gagementwith the second set of bank conta'cts. Since the second contact over which the wiper 167 passes is grounded alsoas well as all thefollowing ones with the exception of the last contact, no eiect is produced by the passin of this wiper to the next contact. Wi r 16 u n comin into engagement associate bank contact, extends the circuit of the impulse stop relay 135 to the first stop. conductor 191. This,

however, does not produce any eect at this time for the reason that the stop conductor 191 is not connected up at any other point.

Impulse relay 133 continues to operate; the bridge across conductors 60 and 61 continues to be opened upon each energization thereof; and the wipers 167 and 168 continue to be advanced step by step inthe manner described until the wiper 168 arrives upon the contact in which the sixth stop conductor 196 `terminates, which is the first stop conductor that is connected u at any other point, at which time the bri across the conductors 60 and 61 will have n opened six times at armature 49 of impulse relay 133. When wiper 168A arrives upon the bank contact in whlch stop conductor 196 terminates, the following circuit lis closed: from ground by way of` `armature 137 of relay 126 and its resting contact, first digit stop conductor 188, workin `contact of armature 181 of relay 175 and sai armature, sixth impulse stop conductor 196, wiper 168, and stop relay 135 to battery. Re-

lay 135, upon energizing, closes a locking circuit for itself at armature 154, includin armature 151 and its workin contact. t

will be noted that a circuit is c osed for relay. 125 in multiple with relay 135 by way of relay 133, while it is yet in a deenergized,

condition, at armature 153; and at armature 155 closes a circuit for stepping magnet 165, which circuit includes armature 166 and its resting contact, and wiper 167 and the bank contact with which it is in engagement. In response to the closure of this circuit the wipers 167 and 168 are ra idly advanced by the buzzer like action o stepping magnet 165, which opens its own circuit at armature 166. This action continues until the said wipers 167 and 168 are advanced into engagement with the last set of contacts when it is stopped because the last contact in the bank of wiper 167 is not grounded. As soon as thewiper 167 passes off the last grounded contact, the circuit of relay 134 is o said relay, being slow releasin 1s maintained energized for an interval. ing, relay 134, replaces the shunt around armature 149 and its resting contact at armature 150, and at armature 151 removes direct ground from the rela s 135 and 125, whereupon relay 126, whic heretofore has been short circuited, and which is connected ,with the grounded start conductor 190, en-

ergzes in series with relays 125 and 135. Upon energizing, relay '126 disconnects relay 135 from in multiple with relay 125 and connectsl it in multi le with relay 127. Re-

lay 135, however, belng slow acting, holds its armature attracted for an interval. As a further result of the energization of relay 126, it disconnects ground from the first digit stop conductor 188 and connects it to the secon digit stop conductor 189 at armature 137. At

pon deenergiz-l penedf but the length relay 135 deenergizes; disconnects stepping magnet from wiper 167 at, armature 155; and at armature .153 connects up impulse relay 133.

The circuits are now in readiness for the second digit 9 to be transmitted, the net result so far accomplished being the opening of the bridge across the conductors 60 and 61 six times and the transferring of the ground potential from the first digit stop conductor 188 to the second digit stop conductor 189. After the last interruption in the bridge across the conductors 60 and 61 a pause has after having been connected u occurred which is determined by the length of time required by the two slow releasing relays 134 and 135 to fall back one after the other. This is done so as to allow time for thechangc over operation from the vertical to the rotary movement to take place in the switch D.

Before describing how the second seriesof interruptions is produced, the eiiect of the first series of interruptions on the switch D in the despatchers oiiice will be considered.'

Each time line relay 39 of the switch D deenergizes in response to one of the interruptions produced in its circuit, it closes a circuit for vertical magnet 4() including ar mature 57 and its resting contact, armature and its working contact, the contact of off normal spring 44 and said spring, series relay 36, and vertical magnet 40. By the operation of the vertical ma net 40, which receives six impulses at this time, the switch shaft and wiper are raised step by step until the latter stands opposite the sixth level of bank contacts which I shall assume is the level shown in the drawing. Relay 36 is energized in series with vertical magnet 40 and being slow releasing retains its armature 52 attracted throughout the Vertical movement, thereby maintaining its own circuit and that of vertical magnet 40 intact afterthe oil normal springs have lshiftted as they doupon thefirst vertical step. At the end of the ver'- tical movement, the series relay 36, upon falling back, shifts the operating circuit from vertical magnet 40 to rotary magnet 41.

vReturning now to the equipment at the substation, when relay 133 energizes again at armature 153 of relay 135 it closes the circuit of stepping magnet 165 at armature 159, whereupon the associated pawl is caused to engage another notch on the ratchet wheel. When iinpulse relay 133 deenergizes again, the wipers 167 and 168 are advanced into engagement with the first set of contacts, whereupon pick up relay 134 energizes in response to wiper 167 coming into engagement with the ground# ed contact, and upon so doing, prepares a locking circuit for relay at armature 151, and at armature removes the shunt from around armature 149 and its resting contact. Relay 133 continues to energize and deenergize in the manner hereinbefore described andat armature 149 opens the bridge across conductors 60 and 61 each Atime it energizes, at the same time operating stepping magnet 165 in the usual manner at armature 159. rlhis operation continues uninterrupted until the wiper 168 comes into engagement with the bank Contact in which the ninth impulse stop conductor 199 terminates, at which time the-bridge across the conductors 60 and 61 will have been opened nine times. When wiper 168 comes into engagement with the bank contact in which the ninth impulse stop conductor 199 terminates, the following circuit is closed: from ground by way of armature 137, of relay 126 and its working contact, the second digit stop conductor 189, the working contact of armature 182 of relay 175 and said armature, stop conductor 199` wiper 168 and stop relay 135 to battery. A branch of this circuit extends by way of armature 164 and its resting contact, armature 138 and its working c0ntact, and relay 127 to battery. Relay 127, upon energizing, prepares a circuit for relay 128 at armature 139 but the said relay 128 does not energize for the time being owing to the fact that it is grounded at both terminals. Stop relay 135, upon energizing, disconnects impulse relay 133 at armature 153; closes a locking circuit for itself and for relay 127 at armature 154; and at armature connects the stepping magnet 165 to wiper 167 through armature 166 and its resting contact. As a result, the wipers 167 and 168 are now advanced step by step by the buzzer like action of stepping magnet until they come into engagement with the last set of bank contacts. iVihen wiper 167 passes oii the last groundedIcontact, the stepping magnet circuit is opened and the circuit of slow releasing relay 134 is opened. Relay 134, upon deenergizing, replaces the shunt around armature 149 and its resting contact at armature 150, and at armature 151 removes direct ground from the circuit of relays 135 and 1271` whereupon relay 128 energizes in series with relay 127, ground being supplied by way of start conductor 190, and upon so doing, disconnects relay 135 from in multiple with relay 127 at armature 164. Relay 135, however, being slow acting, retains its armature attracted for an interval. As a further result of the energizzation of relay 128, it disconnects the grounded conductor from the circuit of impulse relay 133 (the said circuit being open at this time at armature 153) and opens the circuit of relay 130 at armature 140. Relay 130, being slow releasing, retains its armatures attracted for an interval. Returning now to slow releasing relay 135, the said relay, upon deenergizing, closes a point in the circuit of impulse relay 133 at armature 153 but this does not have any eect at this time owing to the fact that the circuit has previously been opened at armature 140 as pointed out. cSilow releasing relay 130, upon deenergizing, re moves the shunt from around the high wound relay 129 at armature 144, whereupon the said relay energizes, thereby moving armature 142 from in engagement with its resting contact. As a further resultvof the decnergization of relay 130, it opens the circuit of relay 131 atarmature 145, but the said relay, being slow releasing, retains its armatures attracted 'for an interval. is a still further result of the denergization of relay 130, it

' relay 173 at armature 180 but the said relay K remains locked up by way of the circuit which includes conductor 303 and armature 176 and its workin contact. As a still further result of the energization of relay 175 it disconnects start con'ductor 190 from ground at armature 179 but the said conductor is still grounded at armature 147 of relay 131, After an interval slow releasing relay 131 falls back; replaces the ground potential upon locking conductor 187 at the normally closed contacts controlled by armature 146; and at armature 147 'removes ground from conductor 190. When kthe ground potential is .removed from conductor 190 the circuit of relays`12'5-128, inclusive, an 132 is opened. Relays 125-128, inclusive, deenergize immediately. Relay 132, however, being slow'releasing, retains its armature attracted for an interval. Relay 132, upon deenergizing after an interval, places ground upon conductor 186 a ain, thereby complet-v ing the entire cycle o operations. The eircuits are `now in readiness to be used over again to transmit another combination of im ulses to the switch D.

the switch D each time line relay 39 deenergizes in response to one of the interruptions of the second series produced in its circuit, it completes the followin circuit: from ground by way of armature 5 and its resting contact, armature 55 andr its working Y contact, normally open contacts controlled by the sixt 0E normalfspring 44, armature 52 audits restingcontact and rotary magnet 41 to battery.

y the operation of rotar magnet 41 which receives nine impulses at t is time, the wiper 58 is rotated step b step until it comes into vengl ement with t e ninth Contactin evel which is the contact 11. Re-

lay 35 is eneiggized in multiple with rotary magnet 41 an being slow releasin retains its armatures attracted through t e rotary movement, thereby maintaining the wi er 58 disconnected and at the same time comp eting the following circuit for ilot relay 4 at armature 51: from groun by way of the working contact of armature 54 and said armature armature 51 and its working contact, shaft operated spring 62 and its resting contact, conductor 59, and pilot relay 4 to iattery. Relay 4, upon energizing, closes a ocking circuit for itself at armature 17;

closes a circuit for the pilot lamp L at armature 16; and at armature 15 closes a circuit circuit of the lamp L and closes the circuit' of the lamp L at armature 21; and at arma ture 20 closes a circuit for the lamp L', the said circuit including the restin contact of spring 19 of the ush button and said spring. As a resu t of these circuit changesI caused by the energization of relay 5 the signal lamp L becomes extinguished and the signal lamp La becomes lighted, and the individual ,pilot lam L becomes lighted to inform the despatcilier in which set of lamps the change has occurred.

After a slight interval, line relay 39 falls back in response to the removal of the shunt from around the high wound relay 129 in the relay group RG', as previously described. Upon falling back, armature 57 of line relay 39 opens the circuit ofrelease -relay 37 and closes the previously traced circuit for rotary magnet 41. Rotary magnet 41, upon energizing, rotates the wiper 58 into engagement with bank contact 12. This, however, does not have-any particular utilit andis merely an incidental occurrence. Re ay 35, upon energizing, in multiplewith -rotary magnet 41 disconnects the wiper 58 before it is moved out of engagement with contact 11 and places ground upon conductor 59 again at armature v 51. The placing of ground upon conductor 59 does not produce any effect at this time because relay 4 is already energized. As a further result of the energization of relay 35, it disconnects amature 56 of rela 38 at armature 50. After a time, release re ay 37 deenerthereby bringing armature 56 out of engagement with its resting contact. As a further result of the deenergization of release relay 37 it opens the circuit of rotary magnet 41 and slow releasin relay 35 at armature 53, at the same time c osin magnet 42'includin o `normal contacts 48. By' the operation o release magnet 42, the shaft and wiper of the switch D are restored to normal position in the usual manner, the circuit of release magnet 42 being opened at off normal contacts 43 by the switch shaft when it reaches normal position. Slow releasing relay 36, upon deenergizing, connects up armature 56 at armature 50, and connects up wiper 58 at armature 51. The circuit conditions and the mechanical position of th vswitch D are now both at normal,

a circuit for release When a signal comes in to the despatchers l oice responsive to some change not brought about by him through the control circuit, the trippin of a circuit breaker for example, the despatc er, upon hearing the buzzer B observes the various common pilot lamps, of

. which only the pilot lamp L is shown, to ascertain from which substation the signal has come and, upon finding out from which substation the signal has come in, he operates the pilot release push button, such as the push l button P, momentarily, thereby opening the locking circuit of the associated pilot relay, such as the pilot relay 4, whereupon the said relay deenergizes; the lamp L becomes extinguished; and the buzzer B ceases to operate. -In the present case, however, the despatcher is walting for the signal and the opi .eration of the pilot relay 4 is merely incidental. The despatcher now knows from the fact that the lamp L2 is extinguished and the lamp La is lighted that the circuit breaker CB* in the substation has been successfully thrown in. In order to extinguish the individual pilot lamp L and to prepare a circuit for it which will be closed when the next sig' be said that the despatcher, having received the signal that the circuit breaker CB* has been thrown in successfully now performs the ,operations necessary in order to operate the starter S, which consists in manipulating the dial ofthe interrupter I so as to send out two series of interruptions to the controlling switch D.l The number of interruptions in the iirst series will correspond to the level of bank contacts in which the starting lead from the starter S terminates, and the number of interruptions inthesecond series will cor# respond to the particular contact in that level in which the said starting lead terminates. The starting lead for the starter S is the conductor 114 and terminates in the bank contact 109 of the switch D', which is the. first contact in the fifth level. Accordingly the first series of interruptions will comprise five interruptions and the second series will comprise only one.

. When the despatcher turns thedial of the interrupter I in accordance with the first digit 5, the various relays of the relay group RG operate in the mannerl described hereinbefore with the result that the high wound relay 67 is short circuited and the line and release relays 90 and 92 of the'switch D are energized, thereby preparing the switch for operation in the manner described hereinbefore. As the dial of the interrupter I returns to its normal position the circuit of line relay 90 of the switch D" is interrupted live-times with the result that the vertical magnet 96 is operated five times, thereby raising the wiper 98 opposite the fifth level of bank contacts. In response to the second manipulation of the interrupter I, the circuit of line relay 90 is interrupted once, whereupon the rotary mag# net 97 operates to step the wiper 98 into engagement with the first bank contact 109 in the fifth level, after which ground is placed upon wiper 98 and consequently upon bank contact 109. As soon as the various relays of the relay group RG- have had time to function, the high wound relay 67 is again inserted in the circuit of line relay 90, whereupon the said `line` relay deenergizes with the result that the switch D is restored to normal position in the previously described manner. As a result of placing the ground potential upon bank contact 109, a circuit is closed by way of conductor 114 for relay 310 associated with the starter S. Relay 310, upon energizing, closes a circuit for relay 311 at armature 317. Relay 311, however, is inductively wound and stiiiiy adjusted so as to make it relatively slow to energize after its circuit is closed and consequently it does not operate for an interval. As a further result of the energization of relay 310, it closes a locking circuit for itself at armature 316, and at armature 315 lcloses the following circuit: from ground .by way of armature 318 and its resting contact, working contact of armature 315 and said armature, and solenoid 334 to battery. Solenoid 334, upon becoming energized, attracts the associatedl plunger, thereby rotating the member 325 in a counter clock wise direction, which through the medium of the connecting rodA shown brings the contactors 326-331, inclusive, into .engagement with their right hand contacts. The contators 329-331, inclusive, upon being operated, connect up the associated auto transformer, and the contactors 326-328, inclusive, connect the secondary taps from the auto transformer to the motor unit of the motor generator MG, whereupon the motor enerator begins to gather speed. When t e initial inrush of current occurs, the marginally adjusted relay 313, which is shunted around the low resistance 314, is operated and at its armature 320.0,pens the circuit of relay 311 before the said relay 311 has had time to energize.

After the speed of the motor generator unit MG has been brought to a point which approximates its running speed, the current iiow decreases sufficiently to allow the marginally adjusted relay 313 to fall back, thereby closing the circuit of relay 311. Relay 311, upon energizing, opens the circuit oi solenoid 334 and closes the circuit of solenoid 333 at armature 318, whereupon thek 'fore it deenergizes.

Jdeenergizes and connects up relay 202.

326-331, inclusive, to the left. The contactors 329-331, inclusive, disconnect the auto transformer, and the contactors 326-328, inclusive, disconnect the motor leads from the secondary windin of the auto transformer andthrow them irect onto the line. When this yis done, the magnet 323, which is shunted aroundthe low resistance 332, attracts the armature 321, thereby locking the member `325 in its operated position. As a further result 'of the operation of armature 321, the

circuit of relay 310 is opened. Relay 310, is

made slightly slow releasing so as to insure that the member 325 is properly locked be- Relay 310, upon deenergizing, opens the circuit of relay 311 at armature, 317. Relay 311, u on deenergizing, opens the circuit of `iolenoid 333 at armature 318. The starter S isl now completely operated and the motor generator MG is running and accordin 1y it remains only tot throw in the circuit reaker CB so as to 'conneet the generator unit in multiple with the generator unit of the motor generator MG.

The deslpatcher is now informed of the fact that t e starting-of the motor generator MG has been completed in a manner that will be described now. In the starter S, when the member 325 is rotated in the clockwise direction, as described, the spring 324 is moved out of engagement with its restin contact and into engagement with its wor ingcontact, thereby removin the ground potential from conductor 302 an placing a ground potential on conductor 301. When the ground potential is removed from conductor 302 relayi`l1169 is, however, does not'- produce any result at this time. When the ground potential is laced upon conductor 301 a circuit is closed or relay 201. Rela 201, upon energizing, removes ound m the armatures 184, 177,

. etc. an closes a circuit for relay 205 at armature 183. fRela 205, upon energizing, closes a locking circuit for itself and opens its initial circuit at armature 212, and at armature 208 closes a circuit for relay 203. Relay 203, upon energizing, o the circuit of relay 201 and closes a l 'n circuit for itself at armature 204. As a rther result of the energization of relay 205, it connects the first digit stop conductor 188 with the first iinpu se stop conductor 191 `at amature 209 and at armature 210 connects the second digit stop conductor 181 with the rst impulse stop conductor 191 also. Thus it will be seen that the firstl series of impulses to be sent t'o the switch D as well as the second series will comprise a single impulse. As a still further result of the energization of relay 205 it laces ground u n start conductor 190 whic prouces the ereinbefore described results in the relay group RG one of-whch is that the high resistance relay 129 is short circuited, whereupon the switch D is prepared for op- .afterwliich relay 126 ener izes an the first set of bank contacts, w ereu on pick up relay 134 energizes and removes t e shunt from around armature 149 and its resting contact of impulse relay 133, at armature 150. Upon the next energization of 'impulse rela 133, the circuit of line relay 39 lof the switc D is interrupted and, u )on the subsequent deener ization of the saiil relay 133, the circuit of ine relay 39 ofthe switch D is closed again and the wipers 167 and 168 are advanced into engagementwith the second set of bank contacts, whereupon the following circuit is closed: from ground by way of the first digit stop conductor 188, working contact of armature 209 and said armature, first impulse stop conductor 191, wiper 168 and relay 135 to battery. Relay 135, upon energizing, disconnects impulse relay 133 at armature 153 and at armature 155 connects operating magnet 165 through its interrupter contacts 166 to wiper 167. The wipers 167 and 168 are now advanced in the previously described manner to their norma osition transfers ground from the first digit stop conducl tor 188 to the second digit stop conductor 189.

After the pianse, caused by the slow releasing relays 134 and 135, impulse `relay 133 is connected up again and the shunt is removed from around armature v149 with the result that another interruption is produced in the circuit off line relay' 39 of the switch D after which the wipers 167 and 168 are again advanced into engagement with their second set of contacts, whereupon stop relay 135 energizes over the following circuit: .from (giround by way of the second digit stop conuctor 189, working contact of armature 210, and said armature, and from thence to battery by way of the previously traced circuit which includes-stop relay 135. Stop relay 135, upon energizin again disconnects impulse relay 133 an connects the operating magnet to wiper 167 with the result that the wipers 167 and 168 are rotated into normal osition. After an interval, the various reays of the relay oup RG operate in the manner described shunt from around high wound relay 129 and to finally restore circuit conditions of all they relays of the relay roup RG to normal.

ereinbefore to remove the` In the switch D, line relay 39, upon deeneri gizing, in response to the first interruption produced in its circuit closes the previously traced circuit for vertical magnet 40 wherer 58 is raised opposite the firstmultiple, whereupon'the wiper 58 is advanced into engagement with the first bank contact in the first level and ground "is placed upon conductor 59, thereby closing a circuit for pilot relay 4 which energizes with the result that the lamp L is lighted and the buzzer B begins to operate. When slow relay 35 falls back, ground is placed upon Wiper 58 and, assuming merely for the 'purpose of illustrationthat the bank contact 10, even though it is not the first Contact in the first level but ii the second contact in the sixth level, is the one with which the wiper 58 is in engagement, relay 6 short circuited the ground potential which is placed uponI ank contact 10 and, upon deenergizing, opens its locking circuit at armature 26; opens the circuit of the lamp L and closes the circuit of the lamp L5 at armature 25; and at armature 24 closes a circuit for the individual pilot lamp L4, the said circuit including the working contact 'of spring 23 and said spring.

Responsive to 'the permanent deenergization of line relay 39, which occurs when the high wound relay 129 of the relay group RG is inserted into its circuit, the switch D is restored tothe normal position in the herein- 'before described manner.

The despatcher, upon being attracted by the buzzer B, observes the pilot lampL, thereby ascertaining from which substation the signal has come in and, by observing the individual pilot lamp L4, ascertains in which group of lamps the change has occurred. The

, despatcher now operates the pushv button P momentarily, whereupon relay 4 dcenergizes; the lamp L becomes extinguished; and the buzzer B ceases to buzz. In order to'extinguish the individual pilot lamp L4 and to prepare another circuit for it, the despatcher pulls out the push button P2, thereby freeing the spring 23 and allowing it yto come into engagement y-with its resting contact, whereupon the'lamp L4 becomes extinguished.

In order to operate the circuit breaker CB2 the-despatcher manipulates the interrupter I first in accordance with the level of contacts in the bank of the switch D in which the conductor 241 terminates, and then in accordance with the particular contact inthe level. As a. result, the wiper 98 is brought into enengagement with the desired contact in a manner described hereinbefore, whereupon ground is placed upon conductor 241, thereby closing a circuit for solenoid 240. Solenoid 240, upon energizing, attractsthe associated plunger, thereby causing the member 246 to be rotated in a clockwise direction. When the member 246 has been operated it is prevented from returning by the notch in the armature of trip magnet 248. As a result of the rotation of the member 246 the contactor 247 is forced into engagement with its associated contact, thereby connecting the generator unit of the motor generator MG with the bus bar 238. The motor generator MG is now in service.

The despatcher is informed that the circuit breaker CB2 has been successfully thrown in in a manner that will be pointed out briefly now. As a still further result of the rotation of the member 246, ground is removed from conductor 244 and is placed upon conductor 243. These conductors (243 and 244) kcorrespond to the conductors 303 and 304 of the circuit breaker CB4 and they accordingly extend to two similar groups of relays the difference being that they are arranged to operate the line relay of the switch D a different number of times when ground is removed from one and placed upon the other. That being the case the switch D is again operated at this time and through the medium of signalsl (not shown) which may be like the ones shown the des atcher is notified of the fact that the circuit breaker CB2 has been successfully `thrown in.

In case the despatcher decides that the current which must be su plied to the trolley wire 235 at some particu ar time, for example, When there are a great many cars running close together and drawing current from this section, is more than the units MG and MG can furnish without being damaged, he may After the current demand has disappeared somewhat, the despatcher may disconnect fthe lead 239 by operating the lnterrupter I in accordance with the correct number, thereby grounding conductor 250 by causing the wiper 98 of the switch D to be brought into engagement with'the bank contact in which the said conductor 250 terminates. When the ground potential is placed upon conductor 250, a circuit is closed for trip magnet 253, whereupon the associated armature isv attracted allowing the circuit breaker CB to return to normal position, thereby disconnecting the lead 239 from the bus bar 238. Itis to be understood that the conductors 251 and 252 correspond to the conductors 303 and 304 of the circuit breaker CB4 and consequently the despatcher is informed of each change of position of the circuit breaker CB.

Assuming that the current demand from this substation decreases still further until the load can be carried by one machine, the despatcher may disconnect the generator unit of the motor generator MG from the bus bar 238 by tripping the circuit breaker CB2.

This operation is performed by suitably manipulating the interrupter I so as to cause the wiper 98 of the switch D to be brought into engagement with the bank contact in which conductor 242 of the circuit breaker CB2 terminates. When this is done a circuit is closed for trip magnet 248, whereupon the associated armature is withdrawn from the member 246 and the circuit breaker returns to normal position. The despatcher is informed that the circuit breaker has been successfully tripped in response to the placing of ground upon conductor 244 which o erates a signal in the despatchers oice in t e previously described manner.

In order to trip the circuit breaker CB,

the despatcher causes the wiper 98 of the controlling switch D t be brought into engage ment with bank contact 112, thereby placing a ground potential vupon conductor 117. When this is done trip magnet 340 energizes disengaging armature 360 from the member 343, whereupon the circuit breaker returns to normal position. In response to the removal of the ground potential from conductor 303 and to the placing of the ground potential upon conductor 304, -relay 173 deenergizes and relay 172 energizes, thereby closing a circuit'for relay 160. Relay 160, upon energizing, in addition to lacing ground upon start conductor 190 and closing a circuit for relay 170, connects the first digit stop conductor 188 to the sixth impulse sto conductor 196 and connects the second digit stop conductor 189 to the tenth impulse stop conduci tor 200. The relays of the relay group now function in tlie usual manner and the wipers 167 and 168 are rotated over the associated bank contacts twice, thereby closin the circuit of the line relay of the switc D, and then reducing two series of interruptions in the said circuit,the first of which comprises six interruptions and the second of which comprises ten interru tions. As a result, the wiper 58 of the switch D is brought into enf agement witb.the tenth contact in the sixth evel of bank contacts, which is the contact 12. When the ground potential is placed upon bank contact 12, subsequent to the wiper 58 being brought into engagement with it, relay 5 is short circuited and accordingly deenergizes. IWhen this occurs the lam L' is extinguished and the lamps L and are lighted. The pilot lamp L is lighted and the p buzzer B is operated in the usual manner.

The despatcher after being informed that the circuit breaker CB has been tripped returns vto push button P to normal, thereby extinguishing the individual pilot lamp L.

In the substation,when the circuit` breaker CB* is tripped the motor generator unit MG stops and t e magnet 323 of the starter S becomes deenergized, whereupon the armature .upon conductor 302. Relay 203 now deenergizes and relay 202 ener izes. Upon energizing, relay 202 closes a circuit for relay 163 at armature 184. Relay 163, upon energizing, in addition to closing the locking cir cuit for itself and placing ground upon start conductor 190 closes a circuit for relay 169 and at the two remainin armatures connects the first digit stop con uctorf188 with the first impulse stop conductor 191 and connects the l second digit stop conductor 189 with the second impulse stop conductor 192. As a result, the associated mechanism o erates in the hereinbefore described manner circuit for the line relay 39 of the switch D and then to produce two series of interruptions in the said circuit the first of which comprises only one interruption and the second of which comprises two interruptions. As a result the wiper 58 is brought into engagement` with the second bank contact in the first level and the associated signals are operated in the usual manner. l

If the despatcher desires to leave the circuit breaker CB.t thrown in he may still disconnect the motor unit of the motor generator MG by causing the wiper of the controlling switch D to be brought into engagement with the bank contact 110, thereby placing a ground potential upon conductor 115. Relay 312, associated with the starter S, upon energizin in res onse to the ground potential being lace upon conductor 115 opens the circuit o magnet 323 at armature 312, whereupon the starter Sis restored to normal position.

In regard to the motor generator MG it may be said that the associated apparatus comprising the circuit breakers CBa and CB and-the starter S are controlled in the same manner as the apparatus associated with the motor generator MG and comprising the circuit breakers CB and CB* and the starter S, respectively. It may be said also that the main circuit breaker CB is controlled in the same manner as any of the others.

It may happen at sometime that one of the control circuits between the des atchers office and the substation is opene by'the breaking of one of the conductors for example, and in order to take care of such an emergency the over load control system comprising t e relay Vgroup RG, Fig. ,4, and the motor M is provided. This over load control s stem is automaticall cut into service and t e despatcher is noti ed, when one of the` control circuits is opened, in a manner which will be explained now. Assuming that one of the two circuits between the des atchers office and the substation is o ened, t e control circuit shown in Fig. 2 an comrst to close a Y armature. 219 by way of armature 230 and its resting prising conductors 83 and 84 for example, the normally energized relays 67 and 91, associated with the relay group RG and the switch D', respectively, deenergize. Relay 67, upon deenergizing, completes the following circuit for relay 2, Fig. 1: from ground by way of armature 76 and its resting contact, armature 8l and its resting contact, armature 73 and its resting contact, conductor 74, and relay 2 to battery. Relay 2,11 on energizing,

closes a circuit for the lamp 7 at armature 27, and at armature 28 closes a circuit for the buzzer B, including spring 29 and its resting contact of the push button P8. The despatcher, upon hearing the buzzer B and upon noting the lighted condition of the lamp L", is informed that the circuit between the relay group RG and the switch D is open and, in order to disconnect the buzzer B and prepare a circuit for it which will be closed upon the subsequent deenergization of relay 2, he operates the push button P3, whereupon the circuit of the buzzer B is opened at spring 23.

In the substation, relay 910i. the switch D', upon deenergizing, places groundupon con.- ductor 113 at armature 100 by way of a circuit which includes armatures 104 and 108 and their resting contacts. When ground is placed upon conductor 113, lit is extended tothe armature 223 of the marginally adjusted control relay 220 of the relay group RG2 and, assuming that the load is below the maximum that can be carried safely by the motor generator MG', in which case armature 223 is retracted as shown, a circuit is closed for slow releasing relay 218 by Way of armature 233and its resting contact, armature 223 and its working contact, and the resting contact of armature 226 and said A circuit is closed also for relay contact. Relay 218, upon energizing, opens the circuit of relay 219 at armature 230 before the said relay has ener ized fully. As a further result of the energlzation of relay 218, it disconnects ground from armature 221 at armature 228 and at armature 229 opens a point in the circuit of relay 217.

Assuming now that the load becomes more than can be safely carried by the motorgenerator MG for more than a short length of time, the marginally adjusted relay 2210 attracts its armature 233,-tl1ereby opening the circuit of slow releasing relay 218 and preparing a circuit for slow releasing relay 217. As soon as slow releasing relay 218 deenergizes it completes a circuit for relay 217 at armature 229, and at armature 230 completes a" circuit for relay 219. Relay 219, upon energizing. connects the trip conductor 242 of the circuit braker CB2 and the trip conductor 117 of the circuit breaker C134 to the working contact of armature 230 at armatures 231 and 232. This however, does not produce any retactor 234 is moved out of engagement with.

the contact on which it normally rests and to which the windingof relay 216 is connected, the said relay 216 deenergizes, thereby opening still another point in the circuit of relay 218 at armature 223.- This is done to prevent the o erations now under way from eing stoppe in a partl finished condition in casethe load should ecrease before they are completed. As a further result of the deenergization of relay 216, armature 225, upon being retracted, moves outof engagement with its worln'ng contact, thereby openingthe initial circuit .of the motor M. Just before this occurs, however, a new circuit for the motor M is completed which includes the grounded contact 254 and the working contact of armature 225. As a still further result of the deenergization of relay 216, it closes a circuit for relay 215 at armature 224. Relay 215, upon energizing, closes a locking circuit for itself at armature 221, which circuit includes amature 228 and its resting contact. As a further result of the energization of relay 215 it opens still another point in the'initial circuit of the motor M at armature 222. As

soon as the contactor 234 comes into engage- /unit of the motor generator MG. The contactor-234 continues to be rotated and remains l in engagement with the contact strip 255 long enough to allow the motor generator MG to be brought up to its ru'nning speed.

After a time the contacter 234 passes ofi' the contact strip 255 and comes into engagement with the Contact which is connected with the solenoid 333 of the starter S. The solenoid 334'now becomes deenergized and the solenoid 333, upon energizing, throws the starter S into running position. The contactor 234, upon coming into engagement with the next Contact, closes a circuit for the solenoid 240 of the circuit breaker CB2, whereu on the said circuit breaker is thrown in in t e usual manner. When this occurs the motor generator MG takes its share of the load.

Upon reaching the starting point, the con-- tactor 234 again closes the circuit of relay 216. U on energizing, relay 216 prepares a circuit or relay 218 at armature 223, and at armature 224 opens the initial circuit of relay 215 but the said relay is maintained energized over its locking circuit which includes armatures 221 and 228. As a still further result of the ener ization of relay 216, it opens the circuit of the motor M at armature 225, armature 222 bein operated at this time. When the circuit o the motor M is opened the said motor stops leaving the contactor 234 in engagement with the contact to which relay 216 is connected.

Assuming now that the load decreases until it can be carried by the motor generator MG', the marginally adjusted relay 220 retracts its armature 223,'thereby 'opening the circuit of relay 217 and preparing a circuit for relay 218. Relay 217, upon deenergizing, opens another point in the circuit of the motor M at armature- 227, and at armature 226 closes the previously traced circuit for relay 218. Relay 218, upon energizing, o ens another point in the circuit of relay 21P7 at armature 229; opens the locking circuit of relay 215 at armature 228, whereupon the said relay 215 deenei'izes and prepares a circuit' for the motor at armature 222. As a further result of the energization of relay 218, it opens the circuit of-relay 219 at arma-- ture 230 and closes a circuit for the trip malgnets 248 and 340 of the circuit breakers C 2 and CB, respectively. Relay 219, being slow releasing, maintains the armatures 231 and 232 attracted for anl interval. In response to the closing of the circuits ,of trip magnets 248 and 340 the circuit breakers CB" and CB4 are tri ped in the usual manner. Relay 219, upon eenergizing, opens the circuit of trip magnets 248 and 340 at armatures 231 and 232. The circuits of the relay group RG2 are now in condition for the motor generator unit MG to be put into service again in case the load becomes too much for the motor generator MG to carry alone.

It may be stated that the reason for making relays 217 and 218 slow releasing is to keep them from responding to momentary changes in the load.

When the circuit comprising conductors 83 and 84, Fig. 2,`is finally repaired, relays 67 and 91 of the relay group RG and the switch D, respectively, energize again. Relay 67, u on energizing, opens the circuit of relay 2, P ig. 1, whereupon the said relay 2 deenergizes; extinguishes'the lamp L1 at armature 27; and at armature 28 closes a circuit for the buzzer B, by way of spring 29 of the push button P3 and its Working contact. The despatcher, upon hearing the buzzer B, notes that the circuit is repaired as indicated by the unli hted condition of the lamp L1 and restores t e push button Pl to normal position, thereby opening the circuit Aof the said buzzer.

comprises essentially a pointer 256 and ay plurality ofcontacts over which the ointer travels, together with the necessary e ement for moving the ointer in accordance with the load. As s own, the pointer 256 is grounded and a conductor is connected to each of the contacts over which it isadapted to pass. `Each of these conductors is assumed to extend to individual relay groups similar to the individual relay groups shown in Fig. 3, to which the conductors 301-304, inclusive, extend. The first of these conductors associ- .ated with the ammeter A is assumed to extend to a relaI group which when actuated in the previous y described manner causes the wiper 58 of the controlling switch D inthe despatchers oflice to be raised to the tenth level of bank contacts and rotated into en agement with the first bank contact in that evel.

In the same Way each of the other relay groups to which the conductors from the ammeter A extend, are connected so as to cause the wiper of th'e controlling switch D in the despatchers ofiice to be raised to the tenth -level of bank contacts, the actuation of the group of relays to which the second conductor is connected causing the wiper of the switch D to be brought into engagement with the second contact in the tenth level, and so on up to the tenth group which causes the wiper to be brought into engagement with the tenth contact in the tenth level.

The tenth level of bank contacts of the switch D is shown in Fig. 9 and comprises the bank contacts 401-410, inclusive, contact 401 .being assumed to be the first contact in the tenth level ,and 410 the tenth.

The ammeter A is assumed to be provided with a graphic recording arrangement which may be of any well known type and is driven by the mot-0r M which has a normally energized field winding, as shown. The armature of the motor M occupies the position of a galvanoineter in the associated Wheatstone bridge, as shown. As long as the bridge is balanced no current flows through the armature but when the bridge becomes unbalanced current fiows through the armature in one direction or to the other depending upon 

